MRC Cancer Cell Unit, Hutchison-MRC Research Centre, Cambridge CB2 0XZ, UK.
Dev Cell. 2010 Feb 16;18(2):317-23. doi: 10.1016/j.devcel.2009.12.016.
Typical murine epidermis has a patterned structure, seen clearly in ear skin, with regular columns of differentiated cells overlying the proliferative basal layer. It has been proposed that each column is a clonal epidermal proliferative unit maintained by a central stem cell and its transit amplifying cell progeny. An alternative hypothesis is that proliferating basal cells have random fate, the probability of generating cycling or differentiated cells being balanced so homeostasis is achieved. The stochastic model seems irreconcilable with an ordered tissue. Here we use lineage tracing to reveal that basal cells generate clones with highly irregular shapes that contribute progeny to multiple columns. Basal cell fate and cell cycle time is random. Cell columns form due to the properties of postmitotic cells. We conclude that the ordered architecture of the epidermis is maintained by a stochastic progenitor cell population, providing a simple and robust mechanism of homeostasis.
典型的鼠类表皮具有图案状结构，在耳部皮肤中清晰可见，分化细胞的规则柱形结构覆盖在增殖的基底细胞层之上。有人提出，每个柱形结构都是由一个中央干细胞及其过渡扩增细胞后代维持的克隆性表皮增殖单位。另一种假说认为，增殖的基底细胞具有随机命运，产生循环或分化细胞的概率是平衡的，从而实现了体内平衡。随机模型似乎与有序组织无法调和。在这里，我们使用谱系追踪来揭示基底细胞产生具有高度不规则形状的克隆，这些克隆为多个柱形结构提供了后代。基底细胞的命运和细胞周期时间是随机的。细胞柱的形成是由于有丝分裂后细胞的特性所致。我们得出结论，表皮的有序结构是由随机祖细胞群体维持的，为体内平衡提供了一种简单而稳健的机制。
